Method and a Device for Heat-Sealing a Film/Foil Onto a Peripheral Top Edge of a Packaging and Such a Packaging

ABSTRACT

The invention relates to a method for sealing an opening of a packaging, in which the packaging includes at least a peripheral wall with a peripheral top edge. The peripheral top edge forms the contour of the opening, including the following process steps: positioning a flexible film/foil layer over the peripheral top edge in such a way that the opening is completely covered and the film/foil layer overhangs beyond the peripheral top edge; heat-sealing the film/foil layer to the peripheral top edge of the packaging; folding the part of the film/foil layer overhanging beyond the opening towards the peripheral wall; heat-sealing the folded-over film/foil layer to the peripheral wall at a distance from the peripheral top edge, in which case a contact point of a device for heat-sealing the folded-over film/foil layer to the peripheral wall at a distance from the peripheral top edge does not move with respect to the film/foil layer during the heat-sealing, at least for as long as the contact point is in contact with the film/foil layer. The invention also relates to a device for heat-sealing according to the above method, and to a packaging manufactured in this way.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the United States national phase of InternationalApplication No. PCT/NL2021/050279 filed Apr. 29, 2021, and claimspriority to Netherlands Patent Application No. 2025465 filed Apr. 30,2020, the disclosures of which are hereby incorporated by reference intheir entirety.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to a method and a device for heat-sealing afilm/foil onto a peripheral top edge of a packaging.

Description of Related Art

Packagings may consist of a more or less dimensionally stable holderwith an opening. In practice, such holders are often covered with a lidand/or by a layer of film/foil material. For decorative purposes, acover made of a film/foil material is sometimes arranged over theopening, such as for example paper or textile, which not only covers theopening, but also hangs down along the periphery of the holder (or thecontour of the holder, respectively). Such a decorative overhanging edgeis also referred to as a “skirt”. The skirt gives a “traditional”appearance to products, such as for example jars filled with pâtés andjam. The skirt may also be clamped securely by the lid or—if attached tothe outside of a lid—may be clamped around the lid and/or an edge of theholder by means of, for example, a piece of string, ribbon or rubberband. However, fitting a skirt in this manner is labour-intensive.

Heat-sealing a film/foil layer onto a packaging is known from the priorart. One of the known ways is to use a heat-shrinking head.

Document DE3047932 discloses a crimping head, which crimping head iscapable of crimping a film/foil around a packaging. Ring parts of thecrimping head can crimp the film/foil around the holder by means of amovement. However, the crimping head is only suitable for crimping afilm/foil. The drawback of this invention is that the invention cannotheat-seal the film/foil onto the packaging. Another drawback of thecrimping head is that there is a considerable risk of damage to thefilm/foil which is to be arranged around the packaging, leading tounsightly effects, damage to the film/foil, or as a result of which anytext is hardly legible by the end user, if at all.

Document GB1085834 describes an apparatus which is capable ofheat-sealing a film/foil onto a peripheral top edge of a packaging. Theremaining film/foil can be crimped against the wall of the packaging bymeans of a pivoting arm. This apparatus is only suitable for producing aheat-seal at one location of the holder. The apparatus is not suitablefor producing heat-seals at multiple locations of a packaging. Anotherdrawback of the apparatus is that the remaining film/foil is pushed overthe packaging, resulting in a bad finish of the packaging. Anotherdrawback of the apparatus from this document is that the overhangingpart of the film/foil is pushed over the packaging by an arm, in whichcase the arm slides across the packaging. The risk of this movementcausing damage to the film/foil during heat-sealing is considerable.

SUMMARY OF THE INVENTION

In this application, the term heat-sealing is, inter alia, understood tomean the following; the actual fusing together of a film/foil to beapplied and the packaging, bonding a film/foil to be applied with thepackaging by means of an applied coating, in which case the coating maybe applied to the packaging and/or the film/foil. It is conceivable forthis fusing and/or bonding to be brought about by way of a coating bymeans of an elevated temperature. However, it is also conceivable forthis fusing and/or bonding to be brought about by way of a coating bymeans of a chemical process. More particularly, such a chemical processmay comprise the use of a bonding agent, such as an adhesive. Thisadhesive may be applied separately or may, for example, already bepresent on one of the two components to be bonded. It is alsoconceivable for the adhesive to be multi-component adhesive, in whichcase one of the two types of adhesive is applied to each of the parts.In certain cases, a chemical process, and in particular the use of anadhesive, may make it possible to effect the bonding without (optionallylocal) heating. In particular, according to the present invention, afilm/foil may be used as a bonding agent, in combination with heating,together with a coating as bonding agent, unheated or in combinationwith heating, or with an adhesive layer as heat-seal medium, unheated orin combination with heating.

The object of the present invention is to offer an alternative methodand a device for efficiently heat-sealing a film/foil on a packaging atmultiple locations which overcomes the abovementioned drawbacks.

To this end, the invention proposes a method for sealing an opening of apackaging, in which the packaging comprises at least a peripheral wallwith a peripheral top edge, which peripheral top edge forms the contourof the opening, comprising the following process steps:

-   -   positioning a flexible film/foil layer over the peripheral top        edge in such a way that the opening is completely covered and        the film/foil layer overhangs beyond the peripheral top edge;    -   heat-sealing the film/foil layer to the peripheral top edge of        the packaging; folding the part of the film/foil layer        overhanging beyond the opening towards the peripheral wall;    -   heat-sealing the folded-over film/foil layer to the peripheral        wall at a distance from the peripheral top edge, in which case a        contact point of a device for heat-sealing the folded-over        film/foil layer to the peripheral wall at a distance from the        peripheral top edge does not move with respect to the film/foil        layer during the heat-sealing, at least for as long as the        contact point is in contact with the film/foil layer.

By means of this method, it is possible to apply a heat-seal to theperipheral top edge and the peripheral wall of a packaging, in whichcase the film/foil is not broken or damaged by the contact point of thedevice. Due to the fact that movement of the device and the film/foilwith respect to each other is avoided at the moment of contact with thefilm/foil layer, the film/foil layer can be applied without damage.Heat-sealing onto the peripheral wall of the packaging takes place at atleast one location on the peripheral wall, and preferably in severallocations.

In an alternative variant embodiment, the heat-seal locations areuniformly distributed on the peripheral wall of the packaging in aperipheral direction. This results in the best distribution of thecontact points and is also good for the uniform bonding of the film/foillayer to the peripheral wall. In an alternative variant embodiment, itis also conceivable for the film/foil layer to be heat-sealed to theperipheral wall in a sealing manner. In a further variant embodiment ofthe method, the contact point approaches the film/foil layer only in adirection towards the peripheral wall and forces the film/foil layertowards the peripheral wall during heat-sealing. By only moving thecontact point in a direction towards the peripheral wall, the presentinvention produces a high-quality heat-seal on the peripheral wall.Preferably, the contact point approaches the peripheral wall of thepackaging in a substantially perpendicular direction.

In another alternative variant embodiment, the part of the film/foillayer overhanging beyond the peripheral top edge is arranged in wave- orzigzag-shaped folds when heat-sealing the film/foil layer against theperipheral wall of the packaging at the at least one heat-seal location.In this way, the local excess of film/foil material is distributed overthe periphery in a controlled manner and, in addition, this may beadvantageous from an aesthetic point of view and may also have aprotective effect due to the voluminous arrangement.

In another alternative variant embodiment, the film/foil layer is alsopunched before and/or during one of the steps a-c. The advantage ofpunching the film/foil is that it can be applied to the packaging in auniform manner, so that all sides or parts of the wall comprise equalamounts of film/foil. Punching of the film/foil may be performed forsteps a-c of a film/foil layer which is wound to form a roll, in whichcase the resulting punched film/foils can immediately be used in theheat-sealing process. In addition, the film/foils may already be orderedin a form which is adapted to a packaging and may subsequently bepositioned above the packaging in such a way, in which case a punchingmember punches the film/foil in such a way that the overhanging part isuniform around the packaging.

In yet another alternative variant embodiment, the at least one contactpoint of the device moves in a substantially circular motion towards theheat-seal location on the peripheral wall of the packaging duringfolding over in step c, the centre of the circle being situated on theperipheral top edge. This movement of the contact point reduces theshear between the contact point of the device and the film/foil layer,or even removes it completely. By removing this shear, the film/foillayer remains intact, which produces a high-quality heat-seal.

In another alternative variant embodiment, the folding in step c isperformed with at least one directional component perpendicular to aplane which is enclosed by the peripheral top edge. In this variantembodiment, the contact point of the device is configured for foldingthe film/foil layer with a directional component which is perpendicularto the enclosed plane, and subsequently heat-sealing the film/foil layeronto the peripheral wall. Folding the film/foil layer with aperpendicular directional component again reduces the shear between thecontact point and the film/foil layer, which results in a heat-seal ofbetter quality. In another variant embodiment, the film/foil layer isheat-sealed to the peripheral top edge so as to be medium-tight with thepackaging. This is advantageous with regard to preventing the foodstuffsfrom perishing and may make additional sealing of the packagingsuperfluous. It also reduces the risk of leakage from the packaging. Itshould be noted that the film/foil layer may be attached to thepackaging so as to be detachable in order to allow access to thecontents of the packaging, and that it is also conceivable for theremoved film/foil layer to be re-attached again and thus to beresealable. Alternatively, the film/foil layer may, on the contrary, beattached in such a way that the packaging can only be opened once bycutting and thus damaging the film/foil. As a result thereof, it isclear to a user of an unopened packaging or film/foil layer that thefood in the packaging is fresh and untouched.

The invention also relates to a device for sealing an opening of apackaging with a film/foil, wherein the packaging comprises at least aperipheral wall with a peripheral top edge, which peripheral top edgeforms the contour of the opening, the device comprising a holder for thepackaging; means for positioning a flexible film/foil layer over theperipheral top edge in such a way that the opening is completely coveredand the film/foil layer overhangs beyond the peripheral top edge; afirst heat-seal element which is movable to and from the opening of apackaging placed in the holder and is configured to heat-seal afilm/foil layer onto the peripheral top edge of a packaging placed inthe holder; a bending element for bending the part of the film/foiloverhanging beyond the peripheral top edge over the peripheral top edgeas far as against the peripheral wall of a packaging; a second heat-sealelement which is movable to and from the peripheral wall of a packagingplaced in the holder, wherein the second heat-seal element, at leastwhen touching the peripheral wall, is only movable perpendicularly tothe plane of the packaging and the film/foil folded against it

The device differs from those of the prior art in that the presentdevice is capable of producing a double heat-seal, the second heat-sealbeing performed by means of a movable heat-seal element, wherein thesecond heat-seal element, at least with one directional component, ismovable substantially perpendicularly to the peripheral wall, andwherein the second heat-seal element is configured to force thefilm/foil layer towards the peripheral wall during heat-sealing.Therefore, the contact point between the device and the film/foil layerdoes not move during the movement, and the entire film/foil layerremains intact. It is important that the film/foil layer does not becomedamaged, as this may contain advertising or other text which may berendered illegible as a result of such damage.

In a further alternative variant embodiment of the device, the devicealso comprises a punching member configured for punching the film/foillayer. Punching the film/foil layer may be performed at various pointsin time. The punching operation may, for example, be performed at thesame time as the application of the heat-seal to the peripheral topedge, but may also be performed after the heat-seal has been applied tothe peripheral top edge and before the film/foil layer is bent.

In an alternative variant embodiment of the device, the bending element,the first and the second heat-seal element are formed by one component.By limiting the number of separate components, a more compact device maybe achieved. In one alternative embodiment, the bending element and thesecond heat-seal element may be the same element, and wherein the firstand the second heat-seal element only differ with respect to each otherin the contact point with the film/foil layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The present method and device will be explained in more detail below bymeans of the following figures, in which

FIGS. 1 a-1 c show a diagrammatic view of the method, and

FIGS. 2 a and 2 b show a diagrammatic view of a variant embodiment ofthe device.

DESCRIPTION OF THE INVENTION

Here, FIGS. 1 a-1 c diagrammatically show the steps of the method forsealing an opening of a packaging 3, wherein the packaging comprises atleast a peripheral wall 4 with a peripheral top edge 1, which peripheraltop edge 1 forms the contour of the opening, comprising the followingprocess steps: positioning a flexible film/foil layer 2 over theperipheral top edge in such a way that the opening is completely coveredand the film/foil layer 2 overhangs beyond the peripheral top edge 1 isillustrated in FIG. 1 a ; heat-sealing 5 the film/foil layer to theperipheral top edge 1 of the packaging 3 is illustrated in FIG. 1 b ;

folding the part of the film/foil layer 2 overhanging beyond the openingtowards the peripheral wall 4; heat-sealing the folded-over film/foillayer 2 to the peripheral wall 4 at a distance from the peripheral topedge 1, in which case a contact point 6 of a device for heat-sealing thefolded-over film/foil layer 2 to the peripheral wall 4 at a distancefrom the peripheral top edge 1 does not move with respect to thefilm/foil layer 2 during the heat-sealing, at least for as long as thecontact point 6 is in contact with the film/foil layer 2, is shown inFIG. 1 c . During folding over, the at least one contact point 6 of thedevice moves in a substantially circular motion 7 towards the heat-seallocation 6 on the peripheral wall 4 of the packaging, the centre of thecircle 5 being situated on the peripheral top edge 1.

FIGS. 2 a and 2 b diagrammatically show the device for sealing anopening of a packaging with a film/foil, wherein the packaging comprisesat least a peripheral wall with a peripheral top edge, which peripheraltop edge forms the contour of the opening, the device comprising aholder for the packaging; means for positioning a flexible film/foillayer over the peripheral top edge in such a way that the opening iscompletely covered and the film/foil layer overhangs beyond theperipheral top edge; a first heat-seal element 9 which is movable to andfrom the opening of a packaging placed in the holder and is configuredto heat-seal a film/foil layer onto the peripheral top edge of apackaging placed in the holder; a bending element for bending the partof the film/foil overhanging beyond the peripheral top edge over theperipheral top edge as far as against the peripheral wall of apackaging; a second heat-seal element 8 which is movable to and from theperipheral wall of a packaging placed in the holder, wherein the secondheat-seal element, at least when touching the peripheral wall, is onlymovable perpendicularly to the plane of the packaging and the film/foilfolded against it.

1. A method for sealing an opening of a packaging, in which the packaging comprises at least a peripheral wall with a peripheral top edge, which peripheral top edge forms the contour of the opening, comprising the following process steps: a. positioning a flexible film/foil layer over the peripheral top edge in such a way that the opening is completely covered and the film/foil layer overhangs beyond the peripheral top edge; b. heat-sealing the film/foil layer to the peripheral top edge of the packaging; c. folding the part of the film/foil layer overhanging beyond the opening towards the peripheral wall; d. heat-sealing the folded-over film/foil layer to the peripheral wall at a distance from the peripheral top edge, wherein a contact point of a device for heat-sealing the folded-over film/foil layer to the peripheral wall at a distance from the peripheral top edge does not move with respect to the film/foil layer during the heat-sealing, at least for as long as the contact point is in contact with the film/foil layer.
 2. The method according to claim 1, wherein the contact point approaches the film/foil layer only in a direction towards the peripheral wall and forces the film/foil layer towards the peripheral wall during heat-sealing.
 3. The method according to claim 1, wherein the heat-seal locations are uniformly distributed on the peripheral wall of the packaging in a peripheral direction.
 4. The method according to claim 1, wherein the part of the film/foil layer overhanging beyond the peripheral top edge is arranged in wave- or zigzag-shaped folds when heat-sealing the film/foil layer against the peripheral wall of the packaging at the at least one heat-seal location.
 5. The method according to claim 1, wherein the at least one contact point moves in a substantially circular motion towards the heat-seal location on the peripheral wall of the packaging during folding over in step c, the centre of the circle being situated on the plane of the peripheral top edge.
 6. The method according to claim 1, wherein the folding in step c is performed with at least one directional component perpendicular to a plane which is enclosed by the peripheral top edge.
 7. The method according to claim 1, wherein the film/foil layer is also punched before and/or during one of the steps a-c.
 8. The method according to claim 1, wherein the film/foil layer is heat-sealed to the peripheral top edge so as to be medium-tight with the packaging.
 9. The method according to claim 1, wherein the heat-seal on the peripheral top edge and/or the peripheral wall of the packaging is detachable.
 10. A device for sealing an opening of a packaging with a film/foil, wherein the packaging comprises at least a peripheral wall with a peripheral top edge, which peripheral top edge forms the contour of the opening, the device comprising a holder for the packaging; means for positioning a flexible film/foil layer over the peripheral top edge in such a way that the opening is completely covered and the film/foil layer overhangs beyond the peripheral top edge; a first heat-seal element which is movable to and from the opening of a packaging placed in the holder and is configured to heat-seal a film/foil layer onto the peripheral top edge of a packaging placed in the holder; a bending element for bending the part of the film/foil overhanging beyond the peripheral top edge over the peripheral top edge as far as against the peripheral wall of a packaging; a second heat-seal element, which is movable to and from the peripheral wall of a packaging placed in the holder, wherein the second heat-seal element, at least when touching the peripheral wall, is only movable perpendicularly to the plane of the packaging and the film/foil folded against it.
 11. The device according to claim 10, wherein the second heat-seal element is at least movable in a direction towards the peripheral wall, and wherein the second heat-seal element is configured to force the film/foil layer towards the peripheral wall during heat-sealing.
 12. The device according to claim 10, wherein the device also comprises a punching member configured for punching the film/foil layer.
 13. The device according to claim 10, wherein the bending element, the first and the second heat-seal element are formed by one component.
 14. A packaging, comprising a bottom, a peripheral wall which extends from the bottom and has a peripheral top edge on the side facing away from the bottom, which peripheral top edge forms the contour of an opening, a flexible film/foil layer which completely covers the opening and overhangs beyond the peripheral top edge, a first heat-seal which extends on and is substantially limited by the peripheral top edge, and a second heat-seal by means of which the part of the film/foil extending beyond the peripheral top edge is bonded to the peripheral wall, at a distance from the peripheral top edge , wherein the first and second heat-seal are produced by fusing at least the film/foil. 